1. Technical Field
The present disclosure relates to a driving apparatus for an electromagnetic load and related method.
2. Description of the Related Art
In driving electronic switch brushless DC motors, the rotor position is determined in order to start from the correct direction, thus avoiding to start from the opposite direction. In hard disk applications, starting from the opposite direction is to be avoided. If the motor is in a rest position, starting from the phase switching in the correct direction is very difficult because the motor, being still, does not generate any counter-electromotive force which could indicate the angular position thereof.
A technique for determining the angular position of the motor is called Inductive Sense. If the windings of the motor are sequentially excited in a three-phase brushless motor, the time employed by the current to reach a default threshold is measured for each exciting step. The inductive sense procedure processes all different response times and it is able to determine the exact position of the rotor by means of different algorithms, thus ensuring a start in the right direction.